I read about using saran wrap and vasaline to make a perfect seal around the hatch cover along with marine grade caulk. First off, I was laughed at at the drug store when I walked out with just saran wrap and vasaline, next time I will buy them separately! Second, the saran wrap was impossible to get to lay perfectly flat so I just coated the whole lip with vasaline and put the caulk on the lip of the hatch then I sealed the hatch. The caulk doesn't stick to vasaline so the saran wrap isn't needed and the excess caulk ooses out the edges filling in the gap between the hatch and the deck making the hatch even more water tight. What I really like about this method is that I only had to build a lip for the hatch to sit flush, I didn't have to recess the lip then build it up with foam sealer. Anyone else try this, was yours water tight?